In a known blood collecting vessel with a collecting tube an axially directed semi-circular tube is provided in the blood feed cap for the supply of blood, with the flat side of the semi-circular tube being bounded by a wall which is upwardly disposed during the taking of blood and which separates a vent passage from the blood passage. The semi-circular tube extends into the centre of the collecting tube and there directly adjoins the inner wall of the collecting tube (US-PS 43 97 318). Outside of the blood feed cap the semi-circular tube is cut-off obliquely so that a scoop-like projection protrudes in the axial direction by means of which blood can be collecting from a blood collecting surface, for example from an ear lobe or a finger. The disadvantage of this known blood collecting vessel is the fact that it must be held inclined to a greater or lesser degree during the taking of blood, and that the width of the front edge of the scoop-like front part of the semi-circular tube which is placed onto the blood taking surface is restricted by the radius of curvature of the semi-circular tube that is used.